random selection

2011 10 30
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I have a matrix size of 96x249.How can i select 48 rows randomly and store it into a new matrix of 48x249.I have values in matrix as decimal numbers.

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Walter Roberson
Walter Roberson 2011-10-30

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T = randperm(96);
NewMatrix = OldMatrix(T(1:48),:);

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Abhiya
Abhiya 2011-11-1
thanks for the answer.do i have an option to store the rest of the matrix after random selection?
Walter Roberson
Walter Roberson 2011-11-1
RestOfMatrix = OldMatrix(T(49:end),:);

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Peter Perkins
Peter Perkins 2011-11-1

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There are a number of ways to do this, including Walter's suggestion. But in addition, if you have access to MATLAB R2011b, there is the slightly simpler
NewMatrix = OldMatrix(randperm(96,48),:);
and if you have access to the Statistics Toolbox in R2011b, there is also
NewMatrix = datasample(OldMatrix,48);
The latter option also allows you to sample with weights, and with replacement. Of course, neither allows you to get the rest of the matrix.
Abhiya
Abhiya 2011-11-4

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My heartful thanks to everybody

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